Need Help solving a PS problem.

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Need Help solving a PS problem.

by navpaktos » Sat Oct 22, 2011 12:20 am
A team scored an average (arithmetic mean) of a points for the first x games of the season, and it scored an average of b points for all y games of the season, where a, b, x, and y are integers and y > x > 0. What was the team's average score for the games played after the first x games?

A. by-ax/y-x
B. ax+by/x+y
C. ax+by/2y
D. by-ax/x+y
E. y/b-x/a

Can anyone explain how do you find the saolution for this problem.
OA is E.

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by shankar.ashwin » Sat Oct 22, 2011 12:27 am
You could substitute numbers to do this.

Say x = 2 games and the team scored 1 point each game.

So in 2 games, a = 2/2 = 1

And y = 4 games where they scored 2 points each.
So in 4 games, b = 8/4 = 2

Your average after x games should be x/a = 2/2 = 1. See which option gives you this.

E for sure satisfies. Check for other options as well :)

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by satishchandra » Sat Oct 22, 2011 12:54 am
navpaktos wrote:A team scored an average (arithmetic mean) of a points for the first x games of the season, and it scored an average of b points for all y games of the season, where a, b, x, and y are integers and y > x > 0. What was the team's average score for the games played after the first x games?

A. by-ax/y-x
B. ax+by/x+y
C. ax+by/2y
D. by-ax/x+y
E. y/b-x/a

Can anyone explain how do you find the saolution for this problem.
OA is E.
Total points earned = by
Pints earned in first x games season = ax

Points earned after x games = by-ax
games played after x games = y-x
Average = (by-ax)/(y-x)

I think the answer should be A